JPH0431421A - Resin composition for prepreg - Google Patents

Abstract

PURPOSE:To obtain the title compsn. curable at low temp. and excellent in storage stability by compounding a reaction product of an epoxy resin with a specific acid and a reaction product of a diisocyanate with a phenol compd. CONSTITUTION:A reaction product of an epoxy resin (e.g. a bisphenol A epoxy resin) with a monobasic acid (e.g. acrylic acid) and a reaction product of a diisocyanate (e.g. tolylene diisocyanate) with a phenol compd. (e.g. m-cresol) are compounded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a resin composition for prepregs, and particularly provides a resin composition for prepregs that can be cured at low temperatures.

(Prior art) Conventionally, epoxy resins used in prepregs often harden at relatively high temperatures (for example, 120 to 180°C), and for this reason, prepregs are bonded to a foam core material such as urethane or acrylic. It was difficult to mold.

Furthermore, in applications such as tooling prepregs, conventional epoxy resins for prepregs cannot be used because of their high curing temperatures.

Furthermore, when manufacturing a composite material using polyethylene fibers or the like as a reinforcing material, conventional epoxy resins for prepregs have the disadvantage that the curing temperature is too high.

Therefore, it has been desired to develop an epoxy resin for prepregs that cures at low temperatures and has excellent storage stability.

(Problems to be Solved by the Invention) The present inventors have conducted extensive studies with the aim of providing a resin composition for prepregs that cures at a lower temperature and has superior storage stability than conventional epoxy resins for prepregs. As a result, the present invention was completed.

(Means for solving the problem) That is, the resin composition for prepreg according to the present invention comprises [A] a reaction product of an epoxy resin and a monobasic acid, and [B]
The constituent component is a reaction product of a diisocyanate compound and a phenol compound.

Any known epoxy resin can be used as the epoxy resin in component [A] of the present invention, and such epoxy resins include, for example, liquid or solid bisphenol A epoxy resin, brominated bisphenol A
type epoxy resin, bisphenol F type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, glycidylamine type epoxy resin, alicyclic epoxy resin, glycidyl ester type epoxy resin, heterocyclic type epoxy resin and other commercially available epoxy resins Examples include resins and the like. Further, reactive diluents such as phenyl glycidyl ether and allyl glycidyl ether can also be mixed with the epoxy resin.

As the epoxy resin in the present invention, bisphenol A type epoxy resin is particularly preferably used.

[A] The monobasic acid in the acid component is -Funazo R-COOH
(R represents hydrogen or an organic residue), and includes compounds with 1 carbon number such as formic acid, acetic acid, acetic acid, and valeric acid.
In addition to saturated monocarboxylic acids having 1 to 20 carbon atoms, unsaturated monocarboxylic acids having 1 to 20 carbon atoms such as crotonic acid, acrylic acid, and methacrylic acid, and aromatic monocarboxylic acids such as benzoic acid are included. Particularly preferred monobasic acids are acrylic acid and methacrylic acid.

In the presence of a solvent, the reaction product of an epoxy resin and a monobasic acid is
Alternatively, it can be obtained by reacting both in the absence, with or without the use of a catalyst. The reaction temperature is usually 50 to 150°C, preferably 80 to 100°C,
The reaction time is usually 2 to 10 hours.

As the solvent, non-reactive solvents such as toluene, xylene, MIBK, etc. can be used. When a solvent is used, it is preferable to distill off the solvent after the reaction is completed.

The catalyst is a tertiary amine such as triethylamine or p-
Toluenesulfonic acid etc. can be used.

Further, a phenolic polymerization inhibitor such as a quinone polymerization inhibitor or a hydroquinone polymerization inhibitor may be used in combination.

The reaction ratio of the epoxy resin and the monobasic acid is 0.5 to 1.5 mol, preferably 0.8 mol, of the monobasic acid per 1 epoxy group.
~1.1 mol. - When the amount of basic acid is less than 0.5 mol, the resin composition of the present invention lacks storage stability. When the amount is more than 1.5 moles, the glass transition temperature of the cured product becomes too low, making it unsuitable as a prepreg resin.

As the diisocyanate compound in component [B],
Examples include alicyclic diisocyanates, aromatic diisocyanates, and aliphatic diisocyanates, and particularly preferred diisocyanate compounds include tolylene diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, and the like.

Phenol compounds include phenol, 0-cresol, m-cresol, p-cresol, 0-nitrocresol, m-nitrocresol, p-nitrocresol, 0-chlorophenol, m-chlorophenol, p-
Examples include chlorophenol, α-naphthol, β-naphthol, etc., and m-cresol, 0-nitrophenol, p-chlorophenol, resorcinol, etc. are preferred.

The reaction between diisocyanate compounds and phenolic compounds is
The reaction can be carried out in the absence of a solvent, without a catalyst or in the presence of a catalyst, and the reaction temperature is usually 20 to 150°C, preferably 3°C.
0 to IO [1°C, reaction time is usually 1 to 10 hours, preferably 2 to 5 hours. As the catalyst, tertiary amines such as triethylamine, dimethylbenzylamine, and 2.4.6-syntylaminophenol, or tin compounds such as dibutyltin dilaurate, dibutyltin dioxide, and dibutyltin diphthylate can be used.

The ratio of component [A] and component [B] is component [A1100
Component [B] is in the range of 5 to 100 parts by weight, preferably 10 to 30 parts by weight.

The resin composition for prepreg of the present invention is usually heated at a temperature of 70 to 100°C.
It cures at low temperatures, and has excellent storage stability, and can be suitably used as a matrix resin for prepregs whose reinforcing fibers are glass fibers, carbon fibers, aramid fibers, polyethylene fibers, etc.

In addition, other resins and additives can be blended into the prepreg resin composition of the present invention as long as they do not impair the purpose of the present invention.

(Effects of the Invention) The resin composition for prepregs of the present invention can be cured at low temperatures, which could not be achieved with conventional epoxy resins for prepregs, so it can be integrally molded with foam materials such as urethane and acrylic that have low heat resistance. It can also be used as a tooling prepreg because it has a high glass transition temperature when post-cured.

(Example) The present invention will be specifically explained with reference to Examples below, but the present invention is not limited thereto.

(Synthesis example) Preparation of component [A (1) 1000 g of Epicoat 828 (bisphenol A type epoxy resin, manufactured by Yuka Shell Epoxy), 390 g of acrylic acid, 1 g of p-toluenesulfonic acid, 1 g of 2.5-diphenyl-p-benzoquinone was added and reacted at 1.30°C for 2 hours to obtain a viscous resin (1).

Preparation of component [A] (2) 450 g of methacrylic acid to 1000 g of Epicote 828
g, 1 g of triethylamine, and 2 g of di-t-butylvalacresol were added, and the mixture was reacted at 140° C. for 1 hour to obtain a viscous resin (2).

Preparation of Component CB] (1) 316 f of m-cresol and 10 g of dibutyltin dilaurate were added to 1740 g of tolylene diisocyanate, and the mixture was reacted at 30° C. for 1 hour to obtain a semi-solid reaction product (3).

Component [Preparation of B (2) p for 500 g of diphenylmethane diisocyanate
- 257 g of chlorophenol was added and reacted at 30°C for 2 hours to obtain a semi-solid reaction product (4).

Example 1 The reactant (
3) 300g was added and mixed uniformly at room temperature. This was impregnated into carbon fiber to create a prepreg. The carbon fiber used had a tensile strength of 350 kg/m+s2s and a tensile modulus of 23t/1.2.

The prepregs obtained in this way were laminated and heated to 80°C.
After curing for 1 hour, a unidirectional flat plate of carbon fiber reinforced plastic (CFRP) with a thickness of 2 mm was obtained.

The carbon fiber volume content of this CFRP was 60% by volume, the tensile strength was 180 kg/m+*2, and the tensile modulus was 12 t/Ryu2.

Further, when this prepreg was bonded to acrylic foam and urethane foam and cured at 80° C. for 1 hour, no deformation was observed in the finished product.

Furthermore, even after leaving this prepreg at room temperature for 50 days,
There were no changes in gel time, resin flow, tack, or drape properties.

Comparative Example 1 Epicote 828 100 parts by weight, dicyandiamide 4
parts by weight and 5 parts by weight of dichlorophenyldimethylurea were mixed to obtain an epoxy resin composition.

When this resin composition was subjected to a curing test, it was found that
It did not harden in 1 hour, but it hardened in 1 hour at 130°C.

This resin composition was impregnated into the same carbon fiber as in Example 1 to obtain a unidirectional blip preg. When this prepreg was bonded to an acrylic foam and cured at 130°C for 1 hour, the finished product was significantly deformed.

Example 2 The reactant (
4) 10 (l g) was added and mixed uniformly at room temperature. The carbon fiber used in Example 1 was impregnated with this to create a prepreg.

The prepregs obtained in this way are laminated in one direction,
It was cured at 80°C for 1 hour. The volume content of carbon fiber in this CFRP is 60% by volume, and the tensile strength is 180k.
g/m2, and the tensile modulus was 12 t/m2.

Further, this prepreg was left at room temperature for 40 days, but there was no change in gel time.

Example 3 2000 g of the resin (1) obtained in the synthesis example, 5 of the reactant (4)
00g was mixed uniformly at room temperature and impregnated into polyethylene fibers to create a prepreg. The tensile strength of the polyethylene fiber used was 350) cg/mu2, and the tensile modulus was Lot/, 2.

The prepregs obtained in this way are laminated in one direction,
It was cured at 80°C for 1 hour. The volume content of polyethylene fibers in this polyethylene fiber reinforced plastic was 60% by volume, the tensile strength was 170 kg/1112, and the tensile modulus was 5.5 t/mm2.

Further, even after this prepreg was left at room temperature for 45 days, there was no change in gel time, resin flow, tack, or drape properties.

Patent applicant: Nippon Oil Co., Ltd.

Claims (1)

[Claims] 1 [A] A reaction product of an epoxy resin and a monobasic acid, and [B
] A resin composition for prepreg comprising a reaction product of a diisocyanate compound and a phenol compound.